英語北師大版一輪復習講練：Part II 語法部分 專題11 情態動詞和虛擬語氣

　　專題十一　情態動詞和虛擬語氣

　　情態動詞

　　一、定義

　　情態動詞表示說話人對某一動作或狀態的態度。

　　二、特點

　　1．有一定詞義；

　　2．不受主語人稱和數的變化影響；

　　3．與主要動詞的原形(或稱不帶to的不定式)一起構成謂語(除ought to作固定詞組看待)。

　　情態動詞無人稱和數的變化， 情態動詞后面跟的動詞需用原形，否定式構成是在情態動詞后面加 “not”。 個別情態動詞有現在式和過去式兩種形式， 過去式用來表達更加客氣， 委婉的語氣， 時態性不強， 可用于過去，現在或將來。情態動詞屬非及物動詞，故沒有被動語態。

　　基本助動詞與情態助動詞最主要的區別之一是，基本助動詞本身沒有詞義，而情態助動詞則有自己的詞義，能表示說話人對有關動作或狀態的看法，或表示主觀設想。

　　三、用法

　　1．can (could)

　　Everyone here can speak English. (表能力)

　　He can't / couldn't have seen her there. (表猜測)

　　He could have gone home. (表猜測)

　　Could / Can I use your pen?

　　Yes, of course you can. (表允許)

　　How can you be so careless? (表懷疑、驚異，主要用于否定、疑問句)

　　Can / Could you lend me a hand? (表委婉發表觀點)

　　2．may (might)

　　You may take whatever you like.(表允許，證據更委婉)

　　注：在回答以may引起的問句時，多避免用這個詞，而用其他方式，如Yes, please. / Certainly. / Please don't. / You'd better not. / No, you mustn't.等，以免顯得太嚴謹或不客氣。

　　They might be having a meeting, but I'm not sure. (表可能)

　　3．must

　　You must buy a ticket. (表義務，意為“必須”)

　　注：回答Must...? 引出的問句時，肯定回答用must; 否定回答不能用mustn't, 而要用needn't或don't have to。

　　—Must I finish my homework now?

　　—Yes, you must.(No, you needn't / don't have to.)

　　This must be Lucy's. (表猜測，意為“想必；準是；一定”等，用于肯定)

　　“must have ＋ 過去分詞”表示“想必”之意，表示對過去的事情的推測。

　　4．shall

　　Shall I play soccer after supper?

　　May I play soccer after supper?

　　If you don't behave yourself, you shall be punished.

　　5．will

　　I will do anything for you. 我愿為你做任何事。 (表意愿，用于各種人稱陳述句)

　　Will you give me a cigarette? Or I will tell the boss.(表請求，用于疑問句)

　　She will stand there sleeping for hours. (表示某種傾向或習慣性動作)

　　6．should

　　You shouldn't be so careless. (表義務，意為“應該”，用于各種人稱)

　　They should have arrived in Beijing by this time. (表推測，意為“想必一定、照說應該、估計”等)

　　It is simply a miracle that rice should grow in such a place. (表示語氣較強的意為“假設；萬一；竟然”)

　　7．would

　　I said I would do anything for you. (表意愿)

　　Would you please tell me the way to the nearest bus stop? (表委婉地提出請求、建議或看法)

　　When he had a problem to solve, he would work at it until he found an answer. (表過去反復發生的動作或過去的一種傾向)

　　8．ought to

　　I really ought to phone my mother.(表義務，意為“應該”，口氣比should稍重)

　　There's a fine sunset; it ought to be a fine day tomorrow. (表推測，暗含很大的可能，語氣較弱)

　　9．used to

　　There used to be a building at the street corner, but it has been pulled down. (表示過去的習慣動作或狀態，現在不再發生或不復存在)

　　I usedn't / didn't use to smoke. (否定式)

　　Used you (Did you use) to go to school on foot? (疑問式)

　　虛擬語氣

　　一、定義

　　虛擬語氣表示說話人的愿望、假設、猜測或建議，而不表示客觀存在的事實。虛擬語氣通過謂語動詞的特殊形式來表示二、用法

　　1．虛擬語氣用于非真實條件句中，一是在if條件狀語從句中；二是在含蓄虛擬條件句中，通過with, without, but for和動詞不定式短語等表示虛擬的條件或句中含有or, or else, otherwise, but等詞語，暗示句子的某一部分(前句或后句)需用虛擬語氣。。

　　? 條件狀語從句 主句

　　與過去事實相反 had ＋ 過去分詞 should / would / could / might ＋ have ＋ 過去分詞

　　與現在事實相反 一般過去時 (be用were) would / should / could / might ＋ 動詞原形

　　與將來事實相反 一般過去時或(should / were to) ＋ 動詞原形 would / should / could / might ＋ 動詞原形

　　If I were you, I would go with them. 假若我是你，我就同他們去。

　　If it hadn't been for your assistance, we wouldn't have succeeded. ＝ But for your assistance, we wouldn't have succeeded. ＝ Without your assistance，we wouldn't have succeeded.要不是你的幫助，我們就不會成功了。

　　If I asked him, I'm sure he'd help us.如果我向他提出要求，肯定他會幫助我們。

　　注意：錯綜時間虛擬條件句，即條件從句與主句所指時間不一致，如從句指過去，而主句即指的是現在或將來，此時應根據具體的語境情況，結合上面提到的三種基本類型對時態作相應的調整。

　　If it had rained last night, the ground would be wet now. 要是昨晚下過雨的話，現在地面就會是濕的。

　　You would be much better now if you had taken my advice. 假若你當時聽我的話，你現在就會好多了。

　　2．虛擬語氣用于主要是表示命令、要求、建議的動詞后的賓語從句中。常見動詞：一個堅持：insist；兩個命令：order, command；三個建議：advise, suggest, propose；五個要求：demand, require, request, desire，ask。這些動詞后面的賓語從句要使用虛擬語氣用法。即從句中的動詞使用should ＋動詞原形，或者將should省略。

　　Mr Johnson insisted that the problem worthy of attention (should) be discussed at the meeting. 約翰森先生堅持應該

　　在會議外討論這個值得注意的問題。

　　He urged that they go to Europe. 他敦促他們到歐洲去。

　　He suggested that we should leave early. 他建議我們早點動身。

　　He ordered that it (should) be sent back. 他命令把它送回去。

　　注意：insist作“堅持說；強調”解時，賓語從句不用虛擬語氣；只有當insist作“堅持(應該)”解時，賓語從句才用虛擬語氣。

　　The stranger we caught insisted that he had never stolen anything. 我們抓住的那個陌生人堅持說他什么東西也沒偷。

　　3．虛擬語氣用于wish后的賓語從句中，表示不能實現的愿望，意為“可惜……；…… 就好了；悔不該……；但愿……”等。表示現在不能實現的愿望，從句的謂語動詞用過去式；表示將來不能實現的愿望，用“would (could)＋動詞原形”；表示過去不能實現的愿望，用“had ＋過去分詞”或“(could) would have＋過去分詞”。

　　She wished she had stayed at home. 她后悔的是她當時要是留在家里就好了。(與過去相反)

　　I wish you would go with us tomorrow.要是你明天同我們一起去就好了。(與將來相反)

　　I wish I were you. 我要是你就好了。(與現在相反)

　　4．虛擬語氣用在would rather后的從句中。若與現在或將來事實不符，從句用一般過去時；若與過去事實不符，從句用過去完成時。

　　I would rather you paid me now. 我希望你現在就給我錢。(與現在事實相反)

　　I would rather you had attended the meeting yesterday. 我希望你昨天參加會議了。(與過去事實相反)

　　5．虛擬語氣用于以as if (as though) 引導的表語從句或狀語從句中。

　　如果從句表示與現在事實相反，謂語動詞用一般過去時；表示與過去事實相反，謂語動詞用“had ＋過去分詞”；表示與將來事實相反，謂語動詞用“would (might, could) ＋動詞原形”。

　　The coach always treats the players as if they were his own children.教練對待隊員就像是對自己的孩子。

　　She was suffering from a bad cold. Her head felt as if it would burst。她正患重感冒，頭疼的感覺就像要炸開一樣。

　　但as if (as though) 后的從句也常用陳述語氣，這是因為從句中的情況往往是可能發生的或可能被設想為真實的。

　　It looks as if it is going to rain. 似乎要下雨。

　　6．虛擬語氣用于if only引導的感嘆句中。

　　If only I knew his name！我要是知道他的名字就好了。

　　If only I had known the answer when my teacher questioned me.老師提問時，我要是知道答案就好了。

　　7．“It's necessary / strange / natural / important ＋ that...”在主語從句中的動詞要用虛擬，即(should)＋動詞原形，表示驚奇、不相信、惋惜、理應如此等。

　　It is important that we (should) have a good knowledge of computer in modern times.在現代社會，有電腦常識是非常重要的。

　　It is necessary that these useful expressions (should) be learnt by heart.我們記住這些有用的表達方式是很有必要的。

　　It is suggested that she should finish her task this afternoon.有人建議她下午就應完成任務。

　　注意：這種從句表示的是事實，如果不表示驚奇，that從句也可用陳述語氣。

　　8．表語從句和同位語從句中的虛擬語氣。

　　在 suggestion, proposal, idea, plan, order, advice 等名詞后面的表語從句、同位語從句中要用虛擬語氣，即 (should) ＋動詞原形。

　　My suggestion is that the project (should) be completed by the end of the year.我建議工程應該在年底前竣工。

　　We all agreed to his suggestion that we (should) go to Beijing for the National Day military parade.他提出去北京看國慶閱兵的建議，我們都非常贊成。

　　9．虛擬語氣用于定語從句

　　這種從句常用在“It is (high) time (that) ...”句型中，定語從句的謂語動詞用過去式，或“should ＋ 動詞原形(should不能省略，be用were)”來表示，意為“(現在)該……”。

　　It's high time that you should stop smoking.你該戒煙了。

　　10．虛擬語氣用于其他幾種結構

　　在某些虛擬語氣結構中沒有if條件句，虛擬條件是用其他形式表示出來，這種現象在語法上稱為“含蓄條件句”。含蓄條件具體分為以下幾種情況：

　　1)通過動詞不定式短語表示條件

　　You would be a fool to refuse his offer. ＝ If you should refuse his offer, you would be a fool. 要是你拒絕他的建議，就太傻了。

　　2)通過介詞短語表達條件

　　But for your help, we couldn't have succeeded. ＝ If it had not been for your help, we wouldn't have succeeded. 要不是你的幫忙，我們就不會成功了。

　　3)通過連詞otherwise, or, but, that, though, once等表達條件

　　She wasn't feeling very well. Otherwise she would have attended the meeting.她本可以參加會議，但是她當時感覺不舒服。

　　4)通過“Were it not for...”或“Had it not been for...”等句式表達條件

　　Were it not for / If it were not for the leadership of the Party, we could not live a happy life.要不是黨的領導，我們不可能過幸福生活。(與現在事實相反)

　　Had it not been for the kind guide, I might have got lost in the mountains.要不是這位好心的向導，我可能就在山中迷路了。 (與過去事實相反)

　　5)通過分詞短語表達條件

　　Given more information, they could have done the job better.倘若給予更多的信息，他們本來可以把工作做得更好。(＝ If they had been given more information...)

　　高考對情態動詞的考查命題熱點主要集中在以下幾個方面：

　　1．注重在語言環境中根據說話人的語氣來使用情態動詞。

　　2．情態動詞表示推測或判斷的用法考查。

　　3．設置場景考查學生熟練使用表示責備等的情態動詞加完成時的用法等。

　　4．虛擬語氣是歷年高考的選考考點，考點常集中在含蓄條件句以及賓語從句中的虛擬語氣上。所設選項常通過謂語動詞的特殊形式來表示， 而且都是結合具體語境來考查對考點的運用能力。今后高考對虛擬語氣的命題重點仍會是在特定語境中考查虛擬語氣中的含蓄虛擬條件句、賓語從句中的謂語動詞等。2011全國卷,32】They

　　have arrived at lunchtime but their flight was delayed.

　　A.will

　　B.can

　　C.must

　　D.should

　　D

　　【考點】考查虛擬語氣的用法。

　　【解析】句意為“他們本該午飯時到達，但他們的航班推遲了。”will have done將來可以完成；can have done可能做過……嗎？表示對過去行為的懷疑，用于疑問句；must have done一定做過某事，表示對過去事情的肯定推測；should have done本來應該做某事，而實際沒做。but their flight was delayed這樣的結果，說明他們本來該到達卻沒有到達，因此選D。

　　2011全國卷II,8】If you

　　smoke, please go outside.

　　A. can

　　B. should

　　C. must

　　D. may

　　C

　　【考點】考查情態動詞的用法。

　　【解析】句意為“如果你非得要抽煙，請到外面去抽。”must (表示主張)一定要，堅持要。根據后一句please go outside的要求，選C。

　　2011北京卷,24】——I don’t really like James. Why did you invite him?

　　Don’t worry. He

　　come. He said he wasn’t certain what his plans were.

　　A. must not

　　B. need not

　　C. would not

　　D. might not

　　【答案】D

　　【考點】考查情態動詞的用法。

　　【解析】句意為“——我真不喜歡James。你為何請了他？——別擔心。他可能來不了。他說他的計劃還沒安排好。”題干中的he wasn’t certain說明他可能不來，可能來，因此使用不完全否定might not。選D。

　　2011北京卷,28】——Where are the children? The dinner’s going to be completely ruined.

　　I wish they

　　always late.

　　A. weren’t

　　B. hadn’t been

　　C. wouldn’t be

　　D. wouldn’t have been

　　【答案】A

　　【考點】考查虛擬語氣的用法。

　　【解析】句意為“——孩子們哪兒去了？這頓飯快要吃不起來了。——我但愿他們不要老是遲到。”wish引出虛擬語氣，題干中出現always，從句虛擬使用一般過去時。選A。

　　2011北京卷,30】Maybe if I

　　science, and not literature then, I would be able to give you more help.